Young-Hwa Kang

Learn More
The female parts of hops (Humulus lupulus L.) show estrogenic effects as well as cancer chemopreventive potential. We analyzed the chemopreventive mechanism of hops by studying its antioxidative activities and its effect on the detoxification of a potentially toxic quinone (menadione). The detoxification enzyme quinone reductase [(NAD(P)H:quinone(More)
In the course of screening for anti-dementia agents from natural products, two beta-secretase (BACE1) inhibitors were isolated from the husk of pomegranate (Punica granatum) by activity-guided purification. They were identified as ellagic acid and punicalagin with IC50 values of 3.9 x10(-6) and 4.1x10(-7) M and Ki values of 2.4x10(-5) and 5.9x10(-7) M,(More)
European elderberry (Sambucus nigra), recognized in Europe for its health-promoting properties for many generations, is known to contain a range of anthocyanins, flavonoids, and other polyphenolics that contribute to the high antioxidant capacity of its berries. American elderberry (Sambucus canadensis), on the other hand, has not been cultivated, bred, and(More)
Activity-guided fractionation of the EtOAc-soluble extract of the whole plants of Sida acuta using a bioassay based on the induction of quinone reductase (QR) in cultured Hepa 1c1c7 mouse hepatoma cells, led to the isolation of ten active compounds of previously known structure, quindolinone (1), cryptolepinone (2), 11-methoxyquindoline (3),(More)
As a result of a bioactivity-guided search for novel, plant-derived cancer chemopreventive agents, ixocarpalactone A (5) was isolated previously as a potent quinone reductase inducer from the leaves and stems of Physalis philadelphica. In the present study, this promising lead compound was reisolated in gram quantities for in vivo biological testing. During(More)
Olive (Olea europaea) contains large quantity of triterpene acids including oleanolic acid (6) as a major one. Varieties of biological activities exhibited by triterpene acids attracted our attentions, especially from pharmaceutical viewpoints. Cell culture of olive plant was induced and its triterpene constituents were studied. From the cell suspension(More)
The bioassay-guided purification of ether extracts of Alpinia officinarum led to the isolation of two new compounds 6-hydroxy-1,7-diphenyl-4-en-3-heptanone (1) and 6-(2-hydroxy-phenyl)-4-methoxy-2-pyrone (4) as well as three known compounds 1,7-diphenyl-4-en-3-heptanone (2), 1,7-diphenyl-5-methoxy-3-heptanone (3), and apigenin (5). Their structures were(More)
Activity-guided fractionation of the petroleum ether and ethyl acetate extracts of the stem bark of Pongamia pinnata, using cultured Hepa 1c1c7 mouse hepatoma cells to evaluate quinone reductase (QR) inducing activity, led to the isolation of four new flavanone derivatives (1-4), one new flavone (5), one new chalcone (6), and 13 known compounds of the(More)
A new butenylflavanone, (2S)-5-hydroxy-7-methoxy-8-[(E)-3-oxo-1-butenyl]flavanone (1), and a new rotenoid, 4',5'-dihydro-11,5'-dihydroxy-4'-methoxytephrosin (2), as well as three active flavonoids of previously known structure, isoliquiritigenin (3), genistein (4), and chrysoeriol (5), along with nine known inactive compounds, alpha-toxicarol (6), sumatrol,(More)